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Explains ringworm causes, symptoms, and progression. Covers how it is diagnosed and treated. Includes information on medicines. Covers behaviors that increase risk of ringworm. Offers prevention and home treatment tips.

Ringworm of the Skin

Topic Overview

Is this topic for you?

This topic is about
ringworm of the skin, groin, or hands. For information about other fungal
infections, see the topics:

What is ringworm of the skin?

Jock itch is a form
of ringworm that causes an itchy rash on the skin of your groin area. It is
much more common in men than in women. Jock itch may be caused by the spread of
athlete's foot fungus to the groin.

What causes ringworm?

Ringworm is not caused by a worm. It is caused by a fungus. The kinds of
fungi (plural of fungus) that cause ringworm live and spread on the top layer
of the skin and on the hair. They grow best in warm, moist areas, such as
locker rooms and swimming pools, and in skin folds.

Ringworm is
contagious. It spreads when you have skin-to-skin contact with a person or
animal that has it. It can also spread when you share things like towels,
clothing, or sports gear.

You can also get ringworm by touching an
infected dog or cat, although this form of ringworm is not common.

What are the symptoms?

Ringworm of the skin
usually causes a very itchy rash. It often makes a pattern in the shape of a
ring, but not always. Sometimes it is just a red,
itchy rash.

Jock itch is a rash in the skin folds of the groin.
It may also spread to the inner thighs or buttocks.

Ringworm of
the hand looks like athlete's foot. The skin on the palm of the hand gets
thick, dry, and scaly. And skin between the fingers may be moist and have open
sores.

How is ringworm of the skin diagnosed?

If you have
a ring-shaped rash, you very likely have ringworm. Your doctor will be able to
tell for sure. He or she will probably look at a scraping from the rash under a
microscope to check for the ringworm fungus.

How is it treated?

Most ringworm of the skin can
be treated at home with creams you can buy without a prescription. Your rash
may clear up soon after you start treatment, but it's important to keep using
the cream for as long as the label or your doctor says. This will help keep the
infection from coming back. If the cream doesn't work, your doctor can
prescribe pills that will kill the fungus.

If ringworm is not
treated, your skin could blister, and the cracks could become infected with
bacteria. If this happens, you will need
antibiotics.

If your child is being
treated for ringworm, you don't have to keep him or her out of school or day
care.

Can you prevent ringworm?

To prevent
ringworm:

Don't share clothing, sports gear, towels, or
sheets. If you think you have been exposed to ringworm, wash your clothes in
hot water with special anti-fungus soap.

Wear slippers or sandals
in locker rooms and public bathing areas.

Shower and shampoo well
after any sport that includes skin-to-skin contact.

Cause

Ringworm
infection is caused by a
fungus. Fungi (plural of fungus) that cause ringworm
live and spread on the outer layer of skin. Ringworm is not caused by a worm or
other parasite.

Fungi are present everywhere in our environment,
including on the human body. They thrive in warm, moist areas, such as locker
rooms and swimming pools, and in skin folds. You can get ringworm of the skin
by sharing contaminated towels, clothing, and sports equipment, and by direct
contact with an infected person.

Ringworm of the skin (tinea corporis) is most commonly caused by the
fungus Trichophyton rubrum, which spreads from one
person to another. It can also be caused by Microsporum canis, which is spread by cats and dogs. This type is less common but
causes a more severe infection.

People often get ringworm of the
groin ("jock itch") by accidentally spreading
athlete's foot fungus to their own groin area. People
who have athlete's foot also commonly spread it to their hands (tinea
manuum).

Some people are more likely to get fungal infections than others. The
tendency to get fungal skin infections or to have them return after treatment
seems to run in families.

With edges that are red and scaly or moist and crusted. The
rash also may have small bumps that look like blisters. The center of the rash
may be clear, giving it a ring-shaped appearance, or there may be a cluster of
red bumps.

That may form large, round patches.

Symptoms of ringworm of the face
include a rash:

On the face, the ears, or
both.

With a border that may not be very distinct.

That
may get worse after being in the sun.

Symptoms of ringworm of the groin
(jock itch) include a rash:

On the groin, skin folds, inner thighs, or
buttocks. The rash usually does not occur on the scrotum or
penis.

With edges that are very distinct and may be scaly or have
bumps that look like blisters.

Ringworm of the
skin may be confused with
other conditions with similar symptoms, such as
eczema or
psoriasis.

What Happens

Ringworm of the skin can start as a small patch of itchy, red, or scaling skin. The rash
can spread and cover a large area.

Clothing that rubs the skin can
irritate the rash. Sweat, heat, or moisture in the air (humidity) can make the
itching and infection worse.

As the infection becomes worse, the
ring-shaped pattern and red-brown color may become
more visible. If not treated, the skin can become irritated and painful. Skin
blisters and cracks can become infected with bacteria and require
antibiotics.

Ringworm can also spread to
other parts of the body, including the feet, nails, scalp, or beard.

After treatment, the rash will go away. But ringworm can return unless
you follow steps to prevent it. The tendency to get fungal skin infections or
to have them return after treatment seems to run in
families.

What Increases Your Risk

Your risk of getting
ringworm is higher if:

You come in contact with a person who has a
fungal infection or with a carrier, a person who has the fungi but does not
have symptoms.

You are
susceptible to fungal infections or you have had a
previous fungal infection.

Exams and Tests

Doctors often can easily recognize
ringworm by its
ring-shaped rash. Your doctor will probably also look
at a skin sample (KOH preparation) under a microscope to confirm that fungus is
present.

Tests for ringworm of the skin include:

A
KOH (potassium hydroxide) preparation. This test can help your doctor find
out whether a fungus is causing your rash. The doctor will take a sample of
your skin by lightly scraping the infected area. The sample is placed on a
slide with potassium hydroxide (KOH) solution and gently heated. If fungus
cells are present, the doctor can then see them with a microscope.

A Wood's light exam. This test may be used to see if the rash is caused by a fungus. Your doctor will shine a special light on your skin where you have the rash. Certain kinds of fungi glow under this light.

A fungal culture (skin culture). This test can identify
the type of fungus that is causing your infection. Usually a culture is only
done if the diagnosis is difficult or the skin condition is not responding to
treatment. This test may take up to 4 weeks, because it takes time for the
fungus to grow.

Treatment Overview

Most cases of
ringworm of the skin, including jock itch and ringworm
of the hand, can be treated with creams or ointments that you put on your skin
to kill fungi. These are called topical antifungals. You can get many topical
antifungals without a prescription. Brand names include Micatin, Tinactin,
Mycelex, and Lamisil.

You may need to take
antifungal pills (oral treatment) if the ringworm does not go away after you
have tried different topical antifungals or if the infection is widespread.
Oral treatments include
azoles such as fluconazole (Diflucan),
allylamines such as terbinafine (Lamisil), and
griseofulvin (Grifulvin V).

Your rash may start to clear up soon after you begin treatment, but it is
important to use the medicine exactly as the label or your doctor says. This
will help keep the infection from coming back. You will probably need to
continue treatment for 2 to 4 weeks.

If not treated, ringworm can
spread and the skin can become irritated and painful. Skin blisters and cracks
can become infected with bacteria. If this happens, you may need to take
antibiotics.

What to think about

You should treat a fungal
infection right away. Severe and widespread infections can be hard to
treat.

Prevention

To prevent
ringworm of the skin:

Keep your skin clean and dry. Change your socks
and underwear at least once a day.

Always dry
yourself completely after showers or baths. After drying your skin with a
towel, allow your skin to air-dry before putting your clothes on. You can also
use a hair dryer, set on a cool setting, to dry your skin.

Do not
share clothing, sports equipment, towels, or sheets. If you think you have been
exposed to ringworm, wash your clothes in hot water with fungus-killing
(fungicidal) soap.

Wear slippers or sandals in locker rooms,
showers, and public bathing areas.

Shower and shampoo thoroughly
after any sport that requires skin-to-skin contact.

If you have
athlete's foot, put your socks on before your
underwear so that fungi do not spread from your feet to your groin. Also, when
toweling off after a shower or bath, dry your feet last.

Take your pet to a veterinarian if it has patches of missing
hair, which may be a sign of a fungal infection. Household pets can spread
fungi that cause ringworm in people.

Home Treatment

In most cases, you can treat
ringworm of the skin with antifungal creams or
ointments. Many are available without a prescription. Use a nonprescription
antifungal cream with miconazole or clotrimazole in it. Brand names include
Micatin, Mycelex, and Tinactin. Terbinafine cream (Lamisil) is also
available without a prescription.

Wash the rash with soap and water, and dry thoroughly. For large
areas of blistered sores, use compresses such as those made with
Burow's solution (available without a prescription) to
soothe and dry out the blisters.

Apply antifungal cream beyond the
edge or border of the rash.

Follow the directions on the package.
Don't stop using the medicine just because your symptoms go away. You will
probably need to continue treatment for 2 to 4 weeks.

If symptoms
do not improve after 2 weeks, call your doctor.

If your rash does not clear after you have tried different
topical antifungals, or if the infection is widespread, you may need
prescription antifungal pills.

If you have both athlete's foot and
ringworm of your groin or legs, you should treat both infections. This will
prevent you from re-infecting your legs or groin with the athlete's foot
fungus, when you put on your underwear.

Medications

Most
ringworm infections of the skin can be treated at home
with nonprescription antifungal creams. The rash will usually improve within 2
weeks. But most antifungals need to be used for 2 to 4 weeks to get rid of the
fungus.1

If the rash does not improve
after you have used an antifungal cream and it is severe and widespread or
returns frequently, you may need antifungal pills that your doctor prescribes.
When you are treating ringworm, it is important to finish the full course of
medicine prescribed, even if the symptoms have gone away, so that the infection
does not return.

Medicine choices

The most common antifungals used to treat
ringworm of the skin are:

Allylamines, such as terbinafine
(Lamisil). Allylamines come as creams, pills, and gels. Terbinafine also comes
as oral granules, which are little grains that can be sprinkled over food and
easily swallowed. Lamisil is available as a cream without a
prescription.

Azoles. Oral prescription forms include
fluconazole (Diflucan) and itraconazole (Sporanox). Some of these medicines are
available without a prescription. Brand names include Micatin and Mycelex.

Griseofulvin (Grifulvin V).
Griseofulvin comes in pill form and requires a prescription.

Other antifungals such as tolnaftate (Tinactin).
Tinactin is available without a prescription and comes in lotion, cream, gel,
and spray forms.

Clotrimazole/betamethasone (Lotrisone), a combination
antifungal and
corticosteroid, is sometimes used to treat ringworm
that is burning, itchy, and inflamed. This prescription medicine should be used
with caution and for no longer than 2 weeks, because complications can occur
with long-term use of corticosteroids.

What to think about

People who are taking antifungal pills should have a doctor
monitor their blood counts and liver and kidney function during treatment to
watch for any harmful side effects.

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